How to Uninstall/Reinstall MDAC

1. Remove the MDAC Exception component keys from HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\ExceptionComponents.
2. Re-run the MDAC 2.81 installer (MDAC_TYP.EXE) or Anyother MDAC Components installer. http://www.microsoft.com/downloads/details.aspx?familyid=78cac895-efc2-4f8e-a9e0-3a1afbd5922e&displaylang=en

MDAC Will be Fixed.
To Make sure MDAC is fixed run below Tool
http://www.microsoft.com/downloads/details.aspx?FamilyId=8F0A8DF6-4A21-4B43-BF53-14332EF092C9&displaylang=en

For windows XP

IF ERROR IS THIS

This setup does not support installing on this operating system.

http://support.microsoft.com/kb/899861

I had a similar experience. Two possible options can be used to allow XP to repair the entries or force the install without having to repair the XP installation.

1. To repair your MDAC installation. Found this solution on the web that works. Have your XP SP2 install disk handy. Go to and find c:\windows\inf\mdac.inf. Right click on the .inf file and pick Install. It will attempt to reinstall the files. Browse to source files on the XP CD. It should install smoothly. It may ask for the handler.reg (in c:\program files\common files\system\msadc\). Restart. Sign in (admin) and then after a few minutes windows update will want to apply the security patch again. You may want to follow up with the SJet update also.

2. To force the installation. Found this one also. XP SP2 will already have the SP1 update applied but has registry corruption (virus after affects). Right click on the MDAC 2.8 SP1 install exe file and select properties. Select the Compatability tab, check the compatability mode box and pick "windows NT" or possibly "Windows 2000". Click apply and run the file again. It should install all the proper files again.



MDAC Component Checker Details
http://support.microsoft.com/kb/307255

ELSE

1. Download the MDAC version you want on the box from:
http://www.msdn.microsoft.com/data/mdac/downloads/default.aspx

2. Open the registry editor by entering the following at a command prompt:
regedit

3. Navigate to the following hive and delete the exception components:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup\ExceptionComponents

Note: this prevent you from overwriting MDAC is they exist therefore they need deleted.

4. navigate to the following hive HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DataAccess

and set the following key to the following value: FullInstallVer, RollbackVersion, and Version to 2.60


Note: when MDAC checker it will see it's old and allow the upgrade to 2.6 SPx or higher


5. Disable anti-virus(very important), stop services such as SQL server, IIS, etc., close applications

6. Run the MDAC_typ.exe from step 1 above to install they version on the box.

7. Reboot and verify the install by running the MDAC Component checker downloadable from

http://www.msdn.microsoft.com/data/mdac/downloads/default.aspx

OR try

1. Windows operating system repair to get to the RTM release of MDAC.

2. Download the version he wanted on the box from http://msdn.microsoft.com/data/mdac/downloads/default.aspx

3. Disable Anti-virus(VERY IMPORTANT), close all applications, stop services such as SQL and IIS, then run the MDAC_tpy.exe for the version downloaded in step 2 above to install it.

4. Verify the install via the MDAC Component Checker also on http://msdn.microsoft.com/data/mdac/downloads/default.aspx

5. Apply Windows updates and hotfixes.